The present invention relates to a rotary compressor having a stationary roller and a rotating cylinder.
In a conventional a rotary compressor, an eccentric roller provided in a cylinder rolls along an inner-wall of the cylinder. discharging the compressed gas in the cylinder. A plurality of slots are formed in the wall of the cylinder. In the slots are arranged respective vanes to separate an intake chamber from a discharge chamber.
FIGS. 11 and 12 show a typical rotary compressor. The rotary compressor comprises a motor 110, a cylinder 20 and stationary plate 10 housed in a housing 100. The motor 110 is a driving means for rotating the cylinder 20.
The stationary plate 10 comprises a plate member 18 having an inlet and an outlet (not shown) and an eccentric shaft 19 extended downward from the lower surface of the plate member 18. The stationary plate 10 sealingly covers the cylinder 20. Further, a stationary cylindrical bearing 120 is arranged at the periphery of the cylinder 20.
An inlet 130 and the outlet 140 penetrate the housing 100 and communicate with an inlet and an outlet (not shown) formed in the stationary plate 10. The latter inlet and the outlet are communicated with an intake chamber 40 and a discharge chamber 50 (FIG. 12) formed in the cylinder 20.
In the side wall of the cylinder 20 are provided two upwardly slots 41,43 in which two vanes 31,33 are slidingly provided. Near respective vanes 31,33 are provided grooves 35,37.
The center P of the shaft 19 of the stationary plate 10 is arranged eccentrically to the rotation center O of the cylinder 20 by a distance E.
The vanes 31,33 are facing each other. In order to always engage the front ends of vanes 31,33 with the periphery of the roller 27, at the rear end of vanes 31,33 there is installed an elastic means 32 of which both ends are fixed to the rear end of vanes 31,33. The elastic means 32 applies to the vanes 31,33 a force which biases both vanes toward the inside of the cylinder 20.
In the operation of the above rotary compressor, with the stationary plate 10 non-rotated, the cylinder 20 is rotated in the direction of the arrow as shown in FIG. 12 by the motor 110. Accordingly, vanes 31,33 are rotated while contacting the periphery of the roller 27 and gas is drawn into the intake chamber 40 of the cylinder 20 through the inlet of the stationary plate 10, and finally the compressed gas is discharged to the outside through the outlet of the stationary plate 10.
However, after a long duration of constant use of the conventional rotary compressor the front ends of vanes 31,33 are severely worn away since they are biased against the periphery of the roller 27 by the force of the elastic means 32. Also the elastic force of the elastic means decreases due to fatigue. Therefore, after the long use time the seal of the intake chamber 40 and the compression chamber 50 can no longer be assured, causing the efficiency of the intake and the discharge to decrease.